The grade predictions are based on previous performance at GCSE, and are accompanied by the pupil's name and photograph.
The school defends the action as 'making students aware' of what they are aiming for in their examinations, which determine allocation of university places in the summer.
But students have said that the tags are 'alienating' and are adding 'unnecessary pressure' to what is already a stressful period.
One student, who wanted to remain anonymous, told Mail Online; 'When we first got them, people were not happy. Many of us were crossing out the grades.
'It makes people who are less academic feel alienated and with exams coming it just adds to the stress.'
The pupil added; 'We were told it was needed so that all students know their targets in case an Ofsted Inspector asks us, which the schools feels is something we should all know.'
Teachers told students that the system had been put in place in light of an upcoming Ofsted inspection and to increase 'safety measures' – enabling staff to challenge anyone on site without ID.
An email from Operational Director Lisa Rattu, which was shared with Mail Online, explained that if students were upset by displaying the predictions they could keep them privately in a diary or on their mobile phone.
But the lanyards were non-negotiable; 'The whole point of this is to make it more difficult for people who shouldn't be here to come on site unnoticed, so it's got to be clearly visible by being worn around your neck in the same way that staff wear them.'
Despite the insistence that students could keep their grades private, the anonymous student explained that there was still a feeling 'they [the grades] are with you at all times'.